INTERSTAGE COUPLERS Interstage Couplers are used to house staging timers and to connect the upper and lower stages together. The Interstage 3000, the latest version from PML, is used in our two-stage rocket kits, but is now available for scratchbuilders designing their own staged rockets. Using an IS3000 system from PML is a quick, simple solution to an often-difficult design problem. Interstage 3000 kits are ready to ship in 2.1, 2.5, 3.0 and 3.9" diameters.

To use an IS-3000 system, the booster needs 3" (regardless of diameter) at the top, just like a regular rocket would for a payload coupler or nosecone shoulder. The sustainer (upper stage) also requires 3" clear at the bottom. Click here for a PDF file that illustrates design requirements for the upper stage. Click here for a file that shows design requirements for the Terrier IS3000.